<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var car = (function(){
            var start = 13;
            var total = 0;
            return {
                price:function(n){
                    if(n <= 3)
                    {
                        total = start;
                    }else{
                        total = start+(n-3)*5;
                    }
                    return total;
                },
                yd:function(flag){
                    return flag?total+10:total;
                }
            };
        })();
        console.log(car.price(5));
        console.log(car.yd(true));
    </script>
</body>
</html>